"Richard Dieter, the executive director of the Death Penalty Information Center, said Tennessee is the first state to enact a law to reintroduce the electric chair without giving prisoners an option. ...

"Dieter said he expects legal challenges to arise if the state decides to go through with an electrocution."

Currently, Tennessee death row inmates can opt for the electric chair instead of lethal injection, but the state gives them a choice. The new law says the state can unilaterally mandate the chair if lethal injection drugs can't be obtained.

"In 2011, the European Union imposed an embargo on exports of drugs used to carry out the death penalty in America, cutting states off from their primary suppliers of sodium thiopental, the anesthetic they had most relied on.

"Some states consequently have tried out new drugs and dosages in recent months. Some have turned to unregulated compounding pharmacies to make the drugs."